I. Field of the Invention
The present invention relates to a method and apparatus for dehumidifying air.
II. Description of the Related Art
A conventional dehumidification apparatus is disclosed in Japanese Laid-open Patent Application (Kokai) No. H8-155247.
As shown in FIGS. 1 and 2, with the dehumidification apparatus disclosed in Japanese Laid-open Patent Application (Kokai) No. 6-324015, a part of the air to be dehumidified, which was inhaled into a housing B of the apparatus by a fan A is transferred to a dehumidification rotor C rotatably mounted in the housing B. After dehumidification by the rotor C, the dehumidified air is discharged to the outside of the housing B. The other part of the inhaled air is passed through passages F of a heat exchanger E and then transferred to the dehumidification rotor C through a heater G to regenerate the dehumidification rotor C. The air humidified by the regeneration of the dehumidification rotor C is then sent to passages H of the heat exchanger E so as to condense the moisture, and the water generated by the condensation of moisture is removed.
However, this apparatus has the following drawbacks:
First, since the humid air generated by the regeneration of the dehumidification rotor C is cooled in the passages H of the heat exchanger E by the air in the vicinity of the housing B to the temperature not higher than the dew point, the air at the exit of the passages H has a temperature somewhat higher than the ambient temperature and has a relative humidity of 100%, so that it contains more moisture than the air in the vicinity of the housing B. Thus, since this humid air cooled by the heat exchanger is discharged to the outside of the housing B as it is, the dehumidification efficiency is not high. Even if the humid air is not discharged but inhaled by the fan A, the humid air is mixed with the air in the vicinity of the housing B, the dehumidification efficiency cannot be greatly promoted.
Second, since the air inhaled by the fan A is divided into two streams and sent to the dehumidification rotor C and heat exchanger E, respectively, the pressure at the entrance of passages K of the dehumidification rotor C is about the same as the pressure at the entrance of the passages F of the heat exchanger E, and the pressure is higher than that of the air in the vicinity of the housing B. The air sent to the passages F of the heat exchanger E is sequentially passed through the heater G, the passages I of the dehumidification rotor C and the passages H of the heat exchanger E, the pressure is sequentially decreased accordingly, and the pressure of the discharged air is about the same as the air in the vicinity of the housing B. Thus, the pressure at the exit of the passages I of the dehumidification rotor C is lower than the entrance of the passages K of the dehumidification rotor C.
Therefore, the air in the vicinity of the entrance of the passages K of the dehumidification rotor C flows to the exit of the passages I of the dehumidification rotor C and the temperature and humidity of the humid air generated at the dehumidification rotor C are both decreased, so that the amount of the removed moisture is decreased.
Third, since the air discharged from the passages K of the dehumidification rotor C is immediately discharged to the outside of the housing B, the pressure in the vicinity of the exit of the passages K of the dehumidification rotor C is about the same as the pressure outside the housing B. Thus, the pressure at the entrance of the passages I of the dehumidification rotor C is higher than the pressure at the exit of the passages K of the dehumidification rotor C. Therefore, a part of the air heated by the heater G in the vicinity of the entrance of the passages I of the dehumidification rotor C flows to the exit of the passages K of the dehumidification rotor C and the amount of the humid air generated by the dehumidification rotor C is decreased, so that the amount of the removed moisture is decreased.